Expandable percutaneous sheath

ABSTRACT

Disclosed is an expandable percutaneous sheath, for introduction into the body while in a first, low cross-sectional area configuration, and subsequent expansion to a second, enlarged cross-sectional configuration. The sheath is maintained in the first, low cross-sectional configuration by a tubular restraint. In one application, the sheath is utilized to provide access for a diagnostic or therapeutic procedure such as percutaneous nephrostomy or urinary bladder access.

PRIORITY INFORMATION

This application claims the priority benefit under 35 U.S.C. § 119(e) ofProvisional Application 60/687,599 filed Jun. 3, 2005, the entirety ofwhich is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to medical devices and, more particularly,to methods and devices for forming a percutaneous channel. In oneapplication, the present invention relates to methods and devices forproviding percutaneous access to a soft tissue or organ.

2. Description of the Related Art

A wide variety of diagnostic or therapeutic procedures involves theintroduction of a device through a natural or artificially createdaccess pathway. A general objective of access systems, which have beendeveloped for this purpose, is to minimize the cross-sectional area ofthe puncture, while maximizing the available space for the diagnostic ortherapeutic instrument. These procedures include, among others, a widevariety of laparoscopic diagnostic and therapeutic interventionalprocedures.

Percutaneous nephrostomy is an example of one type of therapeuticinterventional procedure that requires an artificially created pathway.Percutaneous nephrostomy is a minimally invasive procedure that can beused to provide percutaneous access to the upper urinary tract. Atfirst, percutaneous nephrostomy was used only for urinary diversion butnow it may be used for more complex procedures such as stone extraction,integrate endopyelotomy, and resection of transitional cell carcinoma ofthe upper urinary tract.

In many percutaneous nephrostomy systems, a stiff guidewire is firstplaced into the renal collection system through the renal parenchyma andthe ureter using fluoroscopic control. A second “safety wire” may beplaced with a dual lumen catheter for maintaining the tract should thefirst wire become dislodged or kinked.

Once guidewire control is established, a dilator sheath is used tocreate the tract and establish a rigid working lumen. An early techniqueinvolved advancing a flexible, 8 French, tapered catheter over the firstguidewire to provide guidewire protection as well as a stable path forthe placement of larger diameter dilators and sheaths. The largerdiameter sheaths are sequentially advanced over the catheter and eachother until an approximately 34 French (11 to 12 mm diameter) tract isestablished. The inner sheaths or dilators may then be sequentiallyremoved such that the outermost sheath defines a working lumen. In thissystem, tract formation is accomplished by the angular shearing force ofeach subsequent sheath placement, which cuts a path through the tissue.Because axial pressure is required to advance and place each sheath,care must be taken to avoid kinking the tapered catheter and/oradvancing the sheaths to far and perforating the renal pelvis. Thistechnique also requires a large number of steps.

A more recent technique utilizes a balloon that is advanced over thefirst guide wire. Once in place in the renal pelvis, the balloon isinflated with a dilute contrast media solution to enlarge the tract.Once the balloon is inflated to a suitable diameter, a rigid sheath isadvanced over the balloon. Advancing the rigid sheath over the balloontypically requires applying axial force to the sheath as well asrotation of the sheath relative to the balloon. The balloon may then bedeflated and removed from the rigid sheath so that the rigid sheath maydefine a working lumen. In general, this technique is considered lesstraumatic than the previously described technique. Nevertheless,placement of the rigid sheath still involves angular shearing forces andseveral steps.

Additional information regarding percutaneous nephrostomy can be foundin McDougall, E. M., et al. (2002), Percutaneous Approaches to the UpperUrinary Tract, Campbell's Urology, 8th ed, vol. 4, pp. 3320-3357,Chapter 98, Philadelphia, Saunders.

U.S. Patent Publication No. 2005-0125021, published Jun. 9, 2005 andfiled Jul. 2, 2004, discloses a particularly advantageous access device.However, despite the advantages of this device, there remainsopportunities to provide improved access technology, which allows adevice to be percutaneously passed through a small diameter tissuetract, while accommodating the introduction of relatively large diameterinstruments.

SUMMARY OF THE INVENTION

Accordingly, one aspect of the present invention comprises apercutaneous access system for providing minimally invasive access thatincludes an access sheath having an elongate tubular body that defines alumen. At least a portion of the elongate tubular body is expandablefrom a first, folded, smaller cross-sectional profile to a second,greater cross-sectional profile. The access sheath has a distal end anda proximal end, the proximal end comprises an sheath hub, the sheath hubincluding an anti-rotation member. A releasable jacket is carried by theaccess sheath to restrain at least a portion of the elongate tubularstructure in the first, folded, smaller cross-sectional profile. Anexpandable member is positioned within the elongate tubular body and isconfigured to expand the elongate tubular body from the first, smallercross-sectional profile to the second, greater cross-sectional profile.The expandable member has a distal end and a proximal end. The proximalend includes an expandable member hub with a complementaryanti-rotational member configured to mate with the anti-rotationalmember of the sheath hub and limit rotation between the access sheathand the expandable member.

Another aspect of the present invention comprises a percutaneous accesssystem for providing minimally invasive access that includes an accesssheath comprising an elongate tubular body having a proximal end and adistal end and defining an axial lumen. At least a portion of theelongate tubular body is expandable from a first, smallercross-sectional profile to a second, greater cross-sectional profile. Areleasable jacket is carried by the access sheath to restrain at least aportion of the elongate tubular member in the first, smallercross-sectional profile. An expandable member is positioned within theelongate tubular body and is configured to expand the elongate tubularbody from the first, smaller cross-sectional profile to the second,greater cross-sectional profile. The expandable member comprises anelongated shaft and a balloon having a distal end and a proximal andbeing positioned around the elongated shaft. The distal end of theballoon is bonded to an enlarged diameter portion of the elongatedshaft. The enlarged diameter portion of the elongated shaft has adiameter greater than an average diameter of the elongated shaftpositioned within the elongate tubular body.

Another aspect of the present invention is an percutaneous access systemfor providing minimally invasive access, which comprises an accesssheath having an elongate tubular body having a proximal end and adistal end and defining an axial lumen. At least a portion of theelongate tubular body is expandable from a first, smallercross-sectional profile to a second, greater cross-sectional profile. Areleasable jacket is carried by the access sheath to restrain at least aportion of the elongate tubular member in the first, smallercross-sectional profile. An expandable member is positioned within theelongate tubular body and is configured to expand the elongate tubularbody from the first, smaller cross-sectional profile to the second,greater cross-sectional profile, the an expandable member having adistal end and a proximal end. The expandable member carries at leastone radiopaque member within the access sheath. The access sheathincludes at least one opening in the elongate tubular body, the at leastopening being positioned generally over the at least one radiopaquemember.

Another aspect of the present invention comprises a percutaneous accesssystem, for providing minimally invasive access, which includes anelongate tubular body that defines a lumen. At least a portion of theelongate tubular body is expandable from a first, folded, smallercross-sectional profile to a second, greater cross-sectional profile. Areleasable jacket is carried by the access sheath to restrain at least aportion of the elongate tubular structure in the first, smallercross-sectional profile. An expandable member is positioned within theelongate tubular body and configured to expand the elongate tubular bodyfrom the first, smaller cross-sectional profile to the second, greatercross-sectional profile. Means are provided for preventing rotationabout a longitudinal axis between the elongate tubular body and theexpandable member.

Another aspect of the present invention comprises a percutaneous accessassembly for providing minimally invasive access, which includes anelongate tubular body that defines a lumen. At least a portion of theelongate tubular structure is expandable from a first, folded, smallercross-sectional profile to a second, greater cross-sectional profile.The elongate tubular body has a distal end that forms a distal facewhich includes two beveled faces which are beveled with respect to alongitudinal axis of the elongate tubular body and form a point. Areleasable jacket is carried by the access sheath to restrain at least aportion of the elongate tubular body in the first, smallercross-sectional profile. An expandable member is positioned within theelongate tubular body and is configured to expand the elongate tubularbody from the first, smaller cross-sectional profile to the second,greater cross-sectional profile.

In one embodiment where the percutaneous access sheath is used toprovide access to the upper urinary tract, the percutaneous accesssheath may be used to provide access by tools adapted to perform biopsy,urinary diversion, stone extraction, antegrade endopyelotomy, andresection of transitional cell carcinoma and other diagnostic ortherapeutic procedures of the upper urinary tract or bladder

Other applications of the percutaneous access sheath include a varietyof diagnostic or therapeutic clinical situations, which require accessto the inside of the body, through either an artificially created ornatural body lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a percutaneous access sheath;

FIG. 1A is a front view of the percutaneous access sheath;

FIG. 1B is a front view of the percutaneous access sheath with anunsymmetrical object being passed therethrough;

FIG. 2 is a side elevational view of a jacket;

FIG. 2A is a side elevational view of a modified jacket;

FIG. 2B is a cross sectional view of the jacket of FIG. 2A taken alongline 2B-2B;

FIG. 3 illustrates the percutaneous access sheath in an axially reducedcross-sectional configuration and inserted into the jacket;

FIG. 3A is a schematic lateral cross-sectional illustration of anexemplary embodiment of a folding profile for the sheath of FIG. 3;

FIG. 3B is a schematic lateral cross-sectional illustration of anotherembodiment of a folding profile for the sheath of FIG. 3;

FIG. 3C is a schematic lateral cross-sectional illustration of anotherembodiment of a folding profile for the sheath of FIG. 3;

FIG. 4 is a side elevational view of an access sheath expansion ballooncatheter;

FIG. 5 is an enlarged view of the distal end of the expansion ballooncatheter;

FIG. 5A is an enlarged view of a modified embodiment of the distal endof the expansion balloon catheter;

FIG. 5B is an enlarged view of another modified embodiment of the distalend of the expansion balloon catheter;

FIG. 6 is an enlarged view of the proximal end of the expansion ballooncatheter;

FIG. 7 illustrates the percutaneous access sheath assembly, with theexpansion balloon catheter inserted into the structure illustrated inFIG. 3;

FIG. 8 illustrates the percutaneous access sheath assembly of FIG. 7 inan expanded configuration and the jacket removed;

FIG. 9 illustrates the percutaneous access sheath assembly of FIG. 7inserted into a renal calyx of a kidney, in a first, low profileconfiguration;

FIG. 9A illustrates a modified embodiment of the percutaneous accesssheath assembly of FIG. 7 inserted into a renal calyx of a kidney, in afirst, low profile configuration;

FIG. 10 illustrates the percutaneous access sheath assembly of FIG. 9with the jacket removed;

FIG. 11 illustrates the percutaneous access sheath assembly of FIG. 10with the jacket removed and the expansion catheter fully expanded in asecond, functional configuration;

FIG. 12 illustrates the percutaneous access assembly of FIG. 11 with theexpansion catheter removed;

FIG. 13A illustrates the proximal end of the percutaneous access sheathassembly of FIG. 7 in combination with an extender coupling;

FIG. 13B illustrates the proximal end of the percutaneous access sheathassembly as in FIG. 13A in combination with an extender;

FIG. 13C illustrates the proximal end of the percutaneous access sheathassembly of FIG. 7 with a telescoping member;

FIG. 13D illustrates the proximal end of the percutaneous access sheathassembly as in FIG. 7 with another embodiment of a telescoping member;

FIG. 13E illustrates the proximal end of the percutaneous access sheathassembly of FIG. 13D in an extended position;

FIG. 14A is a schematic partial cross-sectional view of a modifiedembodiment of a percutaneous access sheath assembly;

FIG. 14B is a schematic partial cross-sectional view of the percutaneousaccess sheath assembly as in FIG. 14B with the jacket partiallydisrupted;

FIG. 15A is a cross-sectional view of a modified embodiment of thepercutaneous access sheath assembly of FIG. 7 in an compressedconfiguration;

FIG. 15B is a cross-sectional view of the percutaneous access sheathassembly of FIG. 15A in an expanded configuration;

FIG. 15C is a cross-sectional view of an expansion device of thepercutaneous access sheath assembly of FIG. 15A in a compressedconfiguration;

FIG. 15D is a cross-sectional view an access sheath of the percutaneousaccess sheath assembly of FIG. 1 5A in an expanded configuration;

FIG. 15E is a cross-sectional view of the expansion device of FIG. 15Cin an expanded configuration;

FIG. 16 illustrates a side view of an expandable sheath comprising ananti-rotation feature on the hub;

FIG. 17A illustrates a side view of a collapsed expandable sheathcomprising additional reinforcement in the dilator tubing;

FIG. 17B illustrates a side view of the distal end of an expandedexpandable sheath comprising windows in the outer dilator tubing whichexpose radiopaque markers disposed on the inner tubing; and

FIG. 18 illustrates the distal end of an expanded sheath wherein thesheath tubing comprises two bevels.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an overview of an exemplary embodiment of a percutaneousaccess sheath 100. The sheath 100 generally comprises an elongatetubular body 102 with an axial lumen 108 (FIG. 1A), and is designed toprovide percutaneous access to a site in the body for the purpose ofdiagnosis or treatment.

In the exemplary embodiment, the elongate tubular body 102 has a distalsection 110 and a proximal section 103. The proximal section 103 mayhave a slightly larger inner and outer diameter as compared to thedistal section 110. As will be explained in more detail below, theproximal section 103 may be used to secure the access sheath 100 to aconnector. With continued reference to FIG. 1, the distal end 104 of thedistal section 110 may be provided with a beveled distal face 111, whichpreferably forms an angle of about 45 to about 75 degrees with respect alongitudinal axis of the tubular body 102. In this manner, the distalface 111 forms a leading edge 105 a and a trailing edge 105 b. As willbe explained below, during insertion, the beveled face 111advantageously provides the distal end 104 of the access sheath 100 witha smaller cross-sectional profile in a compressed configuration. Thisprovides a smoother transition from the distal end 104 of the accesssheath 100 to the deployment catheter (described below). In addition, inthe expanded configuration, the leading edge 105 a maintains positionalpurchase within the target tissue or organ while the trailing edge 105 bprovides the sheath 100 with an aperture to facilitate instrumentmaneuvering and visualization within the internal structure of thetissue or organ under examination or treatment. In a modifiedembodiment, the distal face 111 may form an angle of about 90 degreeswith respect to the longitudinal axis of the tubular body.

The length and diameter of the sheath 100 can be varied according toclinical need, as will be understood by those skilled in the art withreference to this disclosure. In one exemplary embodiment forpercutaneous nephrostomy, the access sheath 100 has an overall length ofabout 17 to about 30 centimeters with the distal section 110 having alength of about 11 to about 24 centimeters. As will be explained in moredetail below, a portion or all of the distal section 110 is expandablefrom a first, smaller cross-sectional profile to a second, largercross-sectional profile. The first, smaller cross-sectional profile ofthe distal section 110 eases its insertion into a percutaneous treatmentsite. After insertion, the distal section 110 is expanded to a second,larger cross-sectional profile to provide a larger passageway forsurgical instruments to reach the percutaneous treatment site. Forpercutaneous nephrostomy, the smaller cross-sectional profile may have adiameter of about 15 French to about 24 French and the largercross-sectional profile may have a diameter of about 21 French to about40 French. In the larger cross-sectional profile, the lumen 108 may havea diameter of about 18 French to about 38 French.

In this embodiment, the distal section 110 is creased in at least twoand more preferably 2 to 6 sections, most preferably 2 to 4 sections,and collapsed from a larger to a smaller cross-sectional profile to easeits insertion. As will be explained in more detail below, a jacket 200(see FIGS. 2 and 3) preferably restrains the distal section 110 of thetubing 102 in the smaller cross-sectional profile.

FIG. 3A is a lateral cross-sectional view of the sheath 100 taken alongline 3A-3A of FIG. 3 and illustrates a folding profile for collapsingthe distal section 110 into a smaller cross-sectional profile. In thisembodiment, the distal section 110 includes two creased outer sections111 a, 111 b that lie on the perimeter of the tubing 102 and generallyface each other. Two creased inner sections 113 a and 113 b lie withinthe perimeter of the tubing 102 and generally face away from each other.An additional fold or crease (not shown) may be formed on the section115 of the tubing between the two outer creased sections 111 a, 111 b.The distal section 110 also comprises the inner lumen 108 and thepeel-away sleeve or jacket 210.

FIG. 3B is also a lateral cross-sectional view of the sheath taken alongline 3B-3B. FIG. 3B illustrates a modified embodiment for collapsing thedistal section 110 into a smaller cross-sectional profile. As shown inFIG. 3B, the outer creased sections 111 a, 111 b are overlapped witheach other. In one embodiment, only a portion of the outer creasedsections 111 a, 111 b are overlapped with each other. For example, thedistal edge of the outer creased sections and adjacent portions may beover lapped with each other. Referring to FIGS. 3 and 3B, thisarrangement reduces the cross-sectional profile of the distal end of thedistal section 110 and may provide the distal end with a more taperedcross-sectional configuration to ease insertion of the sheath 100 intothe patient. The peel away sleeve 210 and the collapsed working channel108 are also shown.

FIG. 3C is another lateral cross-sectional view of the sheath 100 takenalong the line 3B-3B of FIG. 3. FIG. 3C illustrates another modifiedembodiment for collapsing the distal section 110 of the sheath 100. Thisembodiment is similar to the embodiment of FIG. 3A. However, in thisembodiment, the two outer creased sections 111 a, 111 b are positionedon the perimeter of the tubing 105 b generally opposite the side of thetubing 102 on which the leading edge 105 a is positioned. In contrast,in the embodiment of FIG. 2A, the two outer creased sections 111 a, 111b are positioned on the perimeter of the tubing generally on the sameside of the tubing 102 on which the leading edge 105 a is positioned. Inthe collapsed configuration, the embodiment of FIG. 3C advantageouslyprovides a more tapered profile at the distal end of the sheath 100. Thepeel away sleeve 210 and the collapsed working channel 108 are alsoshown. The embodiment of FIG. 3C may also be used in combination withthe overlapped configuration described above with reference to FIG. 3B.

In one embodiment for percutaneous nephrostomy, the distal section 110is placed into the renal collecting system through the renal parenchymaand ureters. Its length is thus determined by the anatomy and isgenerally in the range of about 11 cm to about 24 cm. In the illustratedembodiment, the proximal end 103 of the tubing 102 is flared and fittedonto the deployment catheter as will be explained below. The overalllength of the tubing 102 depends on the distance between the insertionand treatment locations, and is generally in the range of 10-100 cm forvarious clinical indications. As mentioned above, for percutaneousnephrostomy, the length of the tubing is approximately 17-30 cm.

As mentioned above, in the illustrated embodiment, the percutaneousaccess sheath 100 comprises a length of tubing 102, which defines alumen 108. In the expanded configuration, the tubing 102 has sufficientstructural integrity to support the surrounding tissue and provide aworking lumen to facilitate instrument maneuvering and visualizationwithin the internal structure of the tissue or organ under examinationor treatment. As explained below, the structural integrity of the tubing102 is determined by a combination of factors including but not limitedto, material, wall thickness to diameter ratio, yield strength,elongation at yield, and the like.

In one embodiment, the tubing 102 is also sufficiently pliable that thecross-sectional shape of the lumen 108 can change in response to theshape of objects drawn therethrough. The tubing may also besubstantially inelastic, in which case the cross-sectional area of theexpanded lumen remains constant, but the shape of the lumen will vary toaccommodate tools (e.g., graspers) and objects (e.g., stones) advancedtherethrough. This arrangement facilitates the passage of unsymmetricalobjects that have a maximum diameter that is larger than the innerdiameter of the tubing 102 in the expanded condition, so long as thegreatest cross-sectional area is no greater than the cross-sectionalarea of the lumen 108.

FIG. 1B illustrates one arrangement where an unsymmetrical object 101 ispassed through the lumen 108. In this arrangement, the tubing issubstantially inelastic. As such, the cross-sectional area of theexpanded lumen remains constant relative to its undistortedconfiguration, shown in FIG. 1A, but the tubing 102 reconfigures as theobject 101 exerts an outward force against the tubing 102. Specifically,the diameter of the tubing 102 in the first direction increases as thediameter of the tubing 102 in the second direction decreases. In oneembodiment, the tubing 102 may reconfigure along one or more of thecreases or folds formed on the distal section 110.

In the alternative, or in combination, the tubing 102 may also compressand/or expand elastically to allow passage of an unsymmetrical objectwith a maximum diameter larger than the diameter of the working lumen108. As the unsymmetrical object is passed through the lumen 108, anoutwardly directed force exerted by the unsymmetrical object causes thediameter of the lumen 108 to increase along one axis while the diameterdecreases along another axis to allow passage of the unsymmetricalobject 101. The use of an elastic or resilient material for the tubing102 will thus allow both the reconfiguration of lumen 108 shape asdiscussed above as well actual enlargement of the cross-sectional areaof the lumen 108 in either a circular or non-circular profile. As thelumen 108 is reconfigured, the tubing 102 may compress and/or expandelastically along one or more of the creases or folds formed on thedistal section 110.

The tubing is preferably also formed from a material that provides a lowcoefficient of friction or high lubricity. The tubing may be made out ofPTFE, FEP, nylon, PEBAX, polypropylene, polyethylene, polyurethane,polyester, silicone, or other suitable materials. Alternatively, any ofa variety of lubricious coatings may be applied to the inside and/oroutside surface of the tubing 102, including PTFE, parylene, and othersknown in the art.

In one exemplary embodiment, the tubing is made out of PTFE and has awall thickness from about 0.010 inches to about 0.024 inches. In oneembodiment, configured for nephrostomy, the tubing 102 is formed fromPTFE, has an outer diameter of about 33 French and a wall thickness ofabout 0.019 inches. The wall thickness to diameter ratio isapproximately 0.044 to about 1 in this embodiment. In anotherembodiment, suitable for ureteral access, the tubing diameter is about0.210 inches (16 French) and the wall thickness is from about 0.009 to0.010 inches.

It should be appreciated that the physical properties of the tubing 102described above represent only some optimized arrangements. Due to theinterplay of the length, material, thickness, number of folds andpossibly other physical characteristics of the tubing, the preferredcharacteristics of the tubing 102 cannot be described in terms of aspecific set of variables. To the contrary, changes in any one variablemay be offsetable by commensurate changes in another variable, toproduce an effective tubing 102 that provides one or more of theadvantages described above. Such optimization can be accomplishedthrough routine experimentation by those of skill in the art in view ofthe disclosure herein, and in view of the objective of providing atubular sheath with one or more of the properties described above. Inaddition, the physical properties of the tubing 102 are dependent on theenvironment of use. For example, the structural integrity of the tubing102 is often a function of the pressure exerted by the surroundingtissue as well as the temperature of the operational surroundings, inthis case at or near a body temperature of 37 degrees centigrade.

FIG. 2 is an overview of the jacket 200. It is preferably made of athin, smooth and flexible material. The jacket 200 has a proximalsection 207 and a distal, restraint section 210. Referring to FIGS. 1and 2, the restraint section 210 has a smaller cross-sectional profilethan the proximal section 207 of the jacket 200. The restraint section210 is adapted to restrain a portion or all of the distal section 110 ofthe percutaneous access sheath 100 in a smaller cross-sectional profile.This is achieved by constraining the percutaneous access sheath 100 inthe jacket 200 such that all or a portion of the distal section 110 ofthe percutaneous access sheath 100 lies within the restraint section 210of the jacket 200.

In the illustrated embodiment, the jacket 200 may be made of heat shrinkPTFE, polyethylene or other suitable materials. The proximal end 202 ofthe jacket 200 terminates at a pull-tab 204, which may be formed by anyof a variety of structures such as, but not limited to, a grasping ring,a knob, or a threaded connector with a Luer lock at its proximal end.The jacket 200 may be provided with a slit 206 near its proximal end202. The jacket 200 tapers at a first tapering point 208 into arestraint section 210, which tapers again into the distal tip 212. Asdiscussed above, the restraint section 210 restrains the distal section110 of the percutaneous access sheath 100 in its smaller cross-sectionalprofile. Thus the length of the restraint section 210 is approximatelythe same as or slightly longer or shorter than the distal section 110,and generally falls within a range of about 11-25 cm.

The outside diameter of the restraint section 210 is preferablyconfigured to ease its insertion into a percutaneous treatment site.Depending upon the clinical application, the outside diameter may be inthe range of about 3 French to about 40 French. For percutaneousnephrostomy, the outside diameter may be in the range of about 5 Frenchto about 35 French. The restraint section 210 is configured to separateand/or tear preferably along its longitudinal axis to release the accesssheath 100 as it is radially expanded. In the illustrated embodiment,the jacket 200 is perforated, scored or otherwise provided with a tearline 215 from the first tapering point 208 to its distal tip 212. Inanother embodiment, the jacket 200 may be constructed of a material thatwill disrupt or separate during expansion from the first tapering point208 to its distal tip 212. In another embodiment, the jacket 200 may beperforated, scored or otherwise provided with a tear line for only aportion of the restraint section 210. For example, in one embodiment,the restraint section 210 may be provided with a tear line at a regionclose to or at the distal end of the jacket 200. This configuration maycause the jacket 200 to disrupt or separate during expansion with theexpansion beginning at its distal end.

The distance between the slit 206 and the distal tip 212 is generallyapproximately equal to or longer than the length of the folded,compressed portion of the tubing 102 such that the folded compressedportion of the tubing 102 terminates within the restraint section 210.In one embodiment, this arrangement permits complete disruption of thejacket 200 when the access sheath 100 is fully expanded. In oneembodiment, the distance between the slit 206 and the distal tip 212 isgenerally in the range of 6-90 cm for most clinical applications andabout 11-24 cm for percutaneous nephrostomy. In the illustratedembodiment, which is configured for percutaneous nephrostomy, thisdistance is approximately 11 cm, and the overall length of the jacket200 is approximately 19 cm.

FIG. 2A illustrates a longitudinal view of a modified peel-away jacketor sleeve 200. As described above, the peel-away jacket 200 comprises apull-tab 204, a slit (not shown), and a distal tip 212. The wall orsleeve 209 of the jacket 200 includes a channel 215, which defines aninner lumen 217 that extends from the pull-tab 204 to the distal tip212. As will be described in more detail below, the inner lumen 217allows passage of a secondary guidewire (not shown), which may be routedthrough the pull-tab 204 and out the distal tip 212. Routing thesecondary guidewire through the inner lumen 217 may protect thesurrounding tissue from potential damage that might be caused by theguidewire and also facilitates guidewire passage because of reducedfriction. Once the peel-away jacket 200 is split apart, the guidewireremains to surround the expandable sheath 100.

FIG. 2B illustrates a lateral cross-sectional view of the peel-awaysheath 200 taken at location 2B-2B in FIG. 2A. The peel-away sheath isdepicted with the wall or sleeve 209, the guidewire channel 215, and theinner lumen 217 of the guidewire channel 215. In the embodiment shown inFIG. 2B, the guidewire channel 215 is affixed or integral to the wall orsleeve 209 on its outer aspect. In another embodiment, the guidewirechannel 215 can be affixed to the internal aspect of the wall or sleeve209 and this arrangement may provide for improved protection of thesurrounding tissues from damage made by the guidewire.

FIG. 3 illustrates the percutaneous access sheath 100 inserted into thejacket 200 via the slit 206 provided near its proximal end 202. Thediameter of the restraint section 210 of the jacket 200 is smaller thanthe diameter of the distal section 110 of the tubing 102. In theillustrated embodiment, the distal section 110 is creased and foldedinwards to decrease its effective diameter, and inserted into therestraint section 210. As discussed above, the restraint section 210restrains the distal section 110 of the percutaneous access sheath 100in its smaller cross-sectional profile. The restraint section 210 may beapproximately the same length as or shorter than the distal section 110.In the illustrated embodiment, the restraint section 210 isapproximately 11-24 cm.

As will be explained in more detail below, in some embodiments, thejacket 200 is removed from the access sheath 100 and the surgical siteafter the sheath 100 is expanded. In other embodiments, the jacket 200is attached to the sheath 100 and remains attached to the sheath 100after it is expanded and during the surgical procedure. In such latterembodiments, the jacket 200 may be securely attached to the accesssheath by, for example, at least one adhesive or heat bond, preferablyextending axially along a section of the access sheath 100 generallyopposite the folds or creases.

In certain embodiments a jacket 200 may not be necessary if the distalsection 110 of the percutaneous access sheath 100 is made of anexpandable material that may be stretched from a first, smallercross-sectional profile to a second, larger cross-sectional profile. Inthese embodiments, the outer surface of the distal section 110 ispreferably made of a smooth material to facilitate the insertion of thepercutaneous access sheath 100 into a treatment site. In still otherembodiments, the jacket 200 may be a stretchable material that may bestretched with or without elastic deformation from a first, smallercross-sectional profile to a second, larger cross-sectional profile asthe sheath is expanded. In yet another embodiment, the jacket 200 maynot be necessary if the sheath is made from a malleable material (seee.g., U.S. Patent Publication No. 2006/0052750, filed Aug. 8, 2005,which is hereby incorporated by referenced herein). In such anembodiment, the sheath 100 can remain in the first, smaller, foldedcross-sectional profile until the sheath 100 is expanded and unfoldedfrom within by the dilator.

FIG. 4 is an overview of the deployment catheter 300. It is providedwith an expansion element such as balloon 310. Referring to FIGS. 1, 1Aand FIG. 4, the deployment catheter 300 is inserted into the lumen 108of the percutaneous access sheath 100 such that the balloon 310 isarranged within the distal section 110. The balloon 310 may then beinflated to expand the distal section 110 from its first, smallercross-sectional profile to its second, larger cross-sectional profilefollowing the insertion of the percutaneous access sheath 100 into atreatment site.

With particular reference to FIG. 4, an inner tube 302 extends theentire length of the deployment catheter 300. A guide wire lumen 304 isdefined by the interior of the inner tube 302. The deployment catheter300 can travel along a guide wire extending through the guide wire lumen304. The inner tube 302 can carry coaxially on its exterior an outertube 306. The outer tube 306 terminates proximally into the distal endof a y-connector 308, and distally into a balloon 310 such that thespace or annulus between the two tubes 302 and 306 forms an inflationlumen for the balloon 310. The balloon 310 may be made of any of avariety of suitable materials, such as, but not limited to, PET,copolymers of polyester, Nylon, PEBAX, Polyurethane, and copolymers ofurethane. The Y-connector 308 may be provided with an optional supporttube (not shown) extending from its distal end and over a proximalsection of the outer tube 306, to increase the rigidity of thedeployment catheter 300 during insertion. This support tube may be madeof any of a variety of materials, such as, a stainless steel hypotube.Alternatively, the two catheter tubes 302 and 306 can be replaced by asingle multi-lumen tube with one lumen capable of passing a guidewiretherethrough and another lumen capable of inflating the balloon throughscythes or fenestrations placed through the tubing wall inside theballoon and operably connecting the balloon interior to the ballooninflation lumen. The distal end of the balloon inflation lumen of themulti-lumen tube is advantageously plugged or sealed to prevent theescape of pressure from the balloon. The proximal end of the ballooninflation lumen is terminated and operably connected with the sideportof the Y-connector 308.

FIG. 5 is an enlarged view of the distal end 314 of the exemplaryembodiment of the deployment catheter 300. Both the inner tube 302 andthe guide wire lumen 304 extend through the distal end 314 of theballoon 310. In the illustrated embodiment, the distal end 314 of theballoon 310 necks down and is attached to a tip 315 at a sealing portion317. The tip 315, in turn, may extend over the distal end of the innertube 302. The inner tube 302 may carry coaxially on its exterior a pairof marker rings 316 a, 316 b near the distal end 314 of the balloon 310.With reference to FIGS. 8, the pair of markers 316 a, 316 b are spacedapart such that when the deployment catheter 300 is inserted into thelumen 108 and expanded they correspond to the distal edge 105 a andproximal edge 105 b of the beveled distal face 111 (see FIG. 1). In amodified arrangement, the markers 316 a and 316 b may be carried by thedistal end 314 of the balloon 310. The markers 316 a and 316 b may bemade of gold, tantalum, platinum or another radio-opaque materialsuitable for visualization under fluoroscopy. Additional markers may beprovided on the deployment catheter to aid in visualizing its location.In another embodiment, the markers 316 a and 316 b may be replaced witha single axially elongated marker having a leading and trailing edgethat corresponds to the distal edge 105 a and proximal edge 105 b of thebeveled distal face 111.

With reference to FIG. 4, a balloon inflation lumen 318, defined in thespace between the inner tube 302 and the outer tube 306, communicateswith the interior of the balloon 310. As discussed above, the balloon310 may be inflated to expand the distal section 110 of the percutaneousaccess sheath 100 from its first, smaller cross-sectional profile to itssecond, larger cross-sectional profile. Thus, the length of the balloon310 is approximately equal to or slightly longer than the length of thedistal section 110. In the illustrated embodiment, which is configuredfor percutaneous nephrostomy, the length of the balloon 310 isapproximately 12.5 cm. For other clinical applications, the length ofthe balloon 310 may be in the range of about 8-90 cm.

FIG. 6 is an enlarged view of the proximal end of the illustratedembodiment of the deployment catheter 300. Both the inner tube 302 andthe guide wire lumen 304 extend through to substantially the distal endof the y-connector 308. The Y-connector 308 may have a hole or lumenthat operably connects to the guidewire lumen 304 to permit completethrough passage of the guidewire or other material. The ballooninflation lumen 318, defined in the space between the inner tube 302 andthe outer tube 306, opens into an inflation port 320 in the Y-connector308. The illustrated embodiment uses a pair of stoppers 322 a, 322 b toalign the inner tube 302 within the Y-connector 308 and prevent theballoon inflation lumen 318 from communicating with the space 324 in themain branch of the Y-connector 308. Thus, only the inflation port 320communicates via the balloon inflation lumen 318 with the interior ofthe balloon. A pump (e.g., a syringe pump) may be connected to theinflation port 320 to inflate or deflate the balloon 310. In a modifiedembodiment, an inflation device or pump (e.g., a syringe pump) may bepre-attached or integrally formed with the port 320. The inflationdevice (not shown) may be pre-loaded with inflation material. To enablevisualization of the state of the balloon 310, it may be inflated withcontrast media. Suitable inflation materials include, but are notlimited to, saline, water, gas, contrast media such as Renografin® orOmnipaque®, or the like. The inflation material is preferably sterile tominimize the risk of infection should a fluid leak occur.

FIG. 7 illustrates the percutaneous access sheath assembly 150 in acollapsed or smaller profile configuration. The percutaneous accesssheath assembly 150 comprises the percutaneous access sheath 100, thejacket 200 and the deployment catheter 300. It is assembled by insertingthe deployment catheter 300 into the percutaneous access sheath 100 andinserting the percutaneous access sheath 100 into the jacket 200 such asvia the slit 206 or other proximal opening provided near its proximalend 202. The balloon 310, which is not shown in FIG. 7, of thedeployment catheter 300 is deflated, folded and inserted into the distalsection 110 of the access sheath 100. The distal section 110, asdiscussed above, is creased and folded inwards to decrease its effectivediameter, and inserted into the restraint section 210 of the jacket 200.As discussed, the balloon 310 is approximately the same length as orjust longer than the distal section 110 and the restraint section 210.

FIG. 5A illustrated a modified embodiment of the distal end 314′ ofpercutaneous access sheath assembly 150. Referring to FIGS. 3 and 5A,inthis embodiment, the sheath assembly 150′ includes a stop 350 forlimiting the distal advance of the jacket 200 in response to force fromthe inflating balloon 310. Referring to FIGS. 4 and 5A, the stop 350 maybe configured in a variety of ways, such as the distal stop 350, whichis coupled to the deployment catheter 300. As the balloon 310 isexpanded, the radial expansion of the balloon 310 may push the jacket200 (see FIG. 7) distally over the distal end of the balloon 310. Thismay prevent the distal end of the jacket 200 from being fully torn orseparated. The distal stop 350 is configured to substantially prevent orreduce this distal migration of the jacket 200 as the balloon 310 isexpanded.

With reference to the illustrated embodiment, the distal stop 350 may beintegrally molded into or attached to the distal end of the balloon 310.The stop 350 includes a proximally facing surface 352, which may contactthe distal end of the jacket 200 to prevent distal movement. Referringto FIGS. 5A and 3, the outer surface of the stop 354 is preferablytapered from its distal end to the proximally facing surface 352 suchthat during assembly the distal tip 210 of the jacket 200 may be pulledproximally over distal stop 350.

In a modified embodiment, the distal stop 350 may comprise a separatecomponent that is coupled to the balloon 310 or to the deploymentcatheter 300. For example, the stop 350 comprises a section of tubing orring that has been bonded or otherwise coupled to the distal end 314 ofthe deployment catheter 310. The tubing may be formed of PET, Hytrel orother suitable materials. In another embodiment, the distal stop 350 isformed form a section of tubing that may be heat shrunk onto the distalend 314 of the deployment catheter 300.

FIG. 5B illustrates another embodiment of the distal end 314″ forreducing the migration of the jacket 200. In this embodiment, the shapeof the distal end 314″ of the balloon 310 is modified to reduce axialforce vectors on the jacket 200 as the balloon 310 is expanded. In theembodiment shown in FIG. 5B, the distal end 314″ of the balloon 310includes a substantially cylindrical section 360, which is generallypositioned adjacent the sealing portion 317 and under the distal end ofthe jacket 200. A tapered section 364 lies proximal to the cylindricalsection 360. This arrangement produces primarily radial force vectors atthe distal tip of the jacket 200 as the balloon 310 is expanded andadvantageously reduces distal migration of the jacket 200. In a modifiedembodiment, the substantially cylindrical section 360 may alternatelyinclude a distal cylindrical taper 366 that may or may not be less thanthe taper of the tapered section 364. For example, in one embodiment,the distal taper end 366 of the substantially cylindrical portion 360tapers at an angle of between about 1 degree to about 90 degrees andpreferably to about 30 degrees to about 60 degrees and the taperedsection 364 tapers from an angle of about 1 degree to about 90 degreesand preferably to about 30 degrees to 60 about degrees.

FIG. 8 illustrates the percutaneous access sheath assembly 150 in anexpanded or larger profile configuration. In the expanded configuration,the jacket 200 has been removed and the balloon 310 has been inflated toexpand the distal section 110 of the access sheath 100. The proximal endof the deployment catheter 300 is shown protruding out the proximal endof the sheath assembly 300.

One exemplary embodiment of use will now be described with reference toFIGS. 9-12, which discloses a schematic representation of a kidney 10.In particular, the kidney 10 includes a central cavity, the renal sinus12, which contains the upper part of the renal pelvis 14 and the calyces16. The calyces 16 are cup shaped tubes, which may vary from seven tothirteen in number and unite to form two or three short tubes that, inturn, join to form the funnel-shaped renal pelvis 14. The renal pelvis14 communicates with the ureter 18, which is partly outside the renalsinus 12. The renal calyces 16 and pelvis 14 together form the upperexpanded end of the excretory duct or renal collection system of thekidney 10. The kidney 10 is composed of an internal medullary andcortical substance 20. A renal capsule 22 covers the kidney 10.

As shown in FIG. 9, a guidewire 400 may be placed through the skin andconnective tissue 22 into the renal collection system 12. In oneembodiment, the guidewire 400 is inserted through the renal parenchymaand the ureter using fluoroscopic control. The guidewire 400 may be0.038″ stiff guidewire that is inserted through a small (e.g., 1.7 totwo centimeter) incision made at the guidewire skin entry cite. A second“safety wire” 402 may be placed with a dual lumen catheter (not shown)for maintaining the tract should the first wire become dislodged orkinked. Guidewire sizes ranging from 0.020 inches to 0.045 inches indiameter may be appropriate for such procedures.

The guide wire 400 may be inserted into the guide wire lumen 304 (seeFIG. 4) of the deployment catheter 300 of the percutaneous access sheathassembly 150. The entire assembly 150 may travel over the guide wire 400until its distal tapered portion is positioned just within the renalpelvis. As mentioned above, the distal tip 314 is preferably providedwith a pair of radiopaque tip markers 316 a and 316 b to aid placement.The jacket 200, which is on the exterior of the percutaneous accesssheath assembly 150, facilitates the insertion because of its smooth,low profile exterior. As mentioned above, in a modified embodiment shownin FIG. 9A, the second safety wire 402 may be positioned within thesecondary lumen 217 (see FIG. 2A) provided in the jacket 200′. In thismanner, the second safety wire 402 may placed when the assembly 150 isadvanced over the guide wire 400. The second safety wire 402 is releasedwhen the jacket is removed as described below. In a modified embodiment,the secondary wire 402 may be placed between the sheath 100 and thejacket 200.

Following the insertion of the percutaneous access sheath assembly 150,the access sheath 100 may be expanded and released from the jacket 200.This may be accomplished by inflating, at least partially, the balloon310 (not visible in FIG. 10) and radially expanding the access sheath100 until the jacket 200 separates, preferably along the longitudinalaxis of the jacket 200. As discussed above, the balloon 310 is arrangedwithin the distal section 110 of the percutaneous access sheath 100,which is itself arranged within the restraint section 210 of the jacket200. Thus, inflating the balloon 310 causes the distal section 110 ofthe percutaneous access sheath 100 to expand, tearing or separating therestraint section 210 of the jacket 200 preferably along itslongitudinal axis.

As shown in FIG. 11, after the sheath 100 is released from the jacket200, the balloon 310 may be fully inflated to expand the distal section110 of the percutaneous access sheath to its full cross-sectionalprofile. In one embodiment, the balloon 310 is inflated by providing apump (e.g., a high pressure balloon inflation syringe) with about 20-25cc or more of a diluted contrast media (e.g., a 50% solution ofRenografin® and sterile saline). After removing the air from the pumpand associated tubing, the pump may be attached to theinflation/deflation port of the central balloon shaft. Preferably, underfluoroscopic control, the dilute contrast media is slowly injected untila maximum pressure of about 12 to 25 bar is achieved. Inflation pressureis preferably maintained for a minimum of about 60 seconds to reduce oreliminate any “waist” (i.e., partially unexpanded sections) that mayremain along the length of the expanded sheath 100.

In some embodiments, after the sheath 100 has been released from thejacket 200, the jacket 200 may be removed from the access sheath 100 andthe surgical site. In other embodiments, the jacket 200 may remainattached to the access sheath 100 during use. As explained above, insuch embodiments, the jacket 200 may be securely attached to the accesssheath by, for example, an adhesive or heat bond.

After the balloon 310 is inflated, it may be deflated to ease theremoval of the deployment catheter 300. As discussed above, theinflation and deflation of the balloon 310 may be done via a pumpconnected to the port 320 of the deployment catheter 300, and preferablywith a dilute radiopaque contrast media being pumped, to better conveythe state of the balloon to an observer by way of fluoroscopic imaging.

In another embodiment, the access sheath 100 may be sequentiallyexpanded. For example, in one embodiment, the length of the balloon 310is smaller than the length of the access sheath 100. In such anembodiment, the access sheath 100 may be expanded in sections as theballoon 310 is sequentially deflated, advanced or withdrawn and thenre-inflated to expand other sections of the access sheath. The accesssheath 100 may be sequentially expanded from the proximal end to thedistal end or from the distal end to the proximal end.

As shown in FIG. 12, with the deployment catheter 300 (not shown)removed, the percutaneous access sheath 100 extends into the renalpelvis 14 and provides a working lumen for instrumentation orinspection. The establishment of this working lumen may provide accessfor several procedures such as biopsy, stone extraction, antegradeendopyelotomy, and resection of transitional cell carcinoma of the upperurinary tract. Referring to FIGS. 1 and 12, in the embodiments with abeveled edge 111, the leading edge 105 a maintains positional purchasewithin the target tissue or organ while the trailing edge 105 b providesthe sheath 100 with an aperture to facilitate instrument maneuvering andvisualization within the internal structure of the tissue or organ underexamination or repair.

In some applications, it may be desirable to lengthen the working lumenafter the access sheath 500 has been wholly or partially deployed. Forthis purpose, FIG. 13A illustrates the proximal end of a modifiedembodiment of a percutaneous access sheath 500, which includes anextender coupling 502 for extending the length of the working lumen 108.

In the illustrated embodiment, the extender coupling 502 is positionedwithin the proximal section 103 of the access sheath 500. A shortproximal portion 506, may be removably coupled to the coupling extender502. The extender coupling 502 and the short proximal portion 506preferably include corresponding retention structures for removablycoupling these two components, 502 and 506, together. Any of a varietyof complementary retention structures may be provided between theextender coupling 502 and the short proximal portion 506 for releasablycoupling these two components. These structures may include, but are notlimited, hooks, latches, prongs, interference fit, press fit, bayonetmounts, threads, and the like. In the illustrated embodiment, thecorresponding retention structures comprise corresponding threads 508 aand 508 b formed on the inner and outer surfaces of the couplingextender 502 and short proximal portion 506 respectively. Threads 508 aand 508 b may comprises a complete 360-degree revolution about thecorresponding part or less than a full revolution such as in a Luer lockor other quick connect configuration.

With continued reference to FIG. 13A, the illustrated access sheath 500optionally includes an instrumentation valve 652 and/or a sealing sleeve654. The sealing sleeve 654 advantageously provides a seal between theshort proximal portion 506 and the exterior of the tubing 102. In theillustrated embodiment, the sleeve 654 comprises a generally tubularbody which is coupled to the distal end of the short proximal portion506 and extends over the junction between the short proximal portion 506and the coupler 502 as shown in FIG. 13A. A sealing member 656 ispositioned on the sleeve 654 between the outer surface of the tubing 102and the sleeve 654. In one embodiment, the sealing member 656 isconfigured to slide over the proximal end 103 of the tubing 102 as theshort proximal portion 506 is coupled to the coupler 502. In thismanner, the sealing member 656 forms a seal between the sheath tubing102 and the sleeve 654 to prevent or minimize fluid escape through thethreaded areas 508 a, 508 b. The sleeve 654 and the sealing member 656may be made of any of a variety of materials, such as, for example,C-flex, polyurethane, silicone elastomer, PTFE, latex rubber,polyethylene, polypropylene, or the like. In other embodiments, thesealing member 656 may be integrally formed with the sleeve 654 and/orthe sealing member 656 may be formed on the proximal end 103 of thetubing 102. In another embodiment, the sleeve 654 may be coupled orintegrally formed with the proximal end 103 of the tubing 102.

In the illustrated embodiment, the instrumentation valve 652 positionedwithin the coupler 502 and is configured to prevent or minimize theescape of fluids between the coupler 502 and any instrumentation, whichmight be inserted therethrough. Any of a variety of structures may beused to prevent or minimize the escape of fluids between the coupler 502and any instrumentation inserted therethrough, such as, for example,duck bill valves, Touhy-Borst valves, donut valves, diaphragms with acentral slit or hole and the like. The instrumentation valve 652 may bemade from any of a variety of materials, such as, for example, C-flex,polyurethane, silicone elastomer, PTFE, latex rubber, polyethylene,polypropylene, or the like. As mentioned above, the instrumentationvalve 652 is advantageously configured to provide a seal around theoutside of any instrumentation passed therethrough and may further sealto itself without the need for any cylindrical or axially elongateinstrumentation, such as a catheter, being inserted therethrough. Theuse of the instrumentation valve 652, located distally to the threadedarea 508 a and 508 b as illustrated in FIGS. 13A and 13B, may reduce oreliminate the need to provide a seal against fluid loss at the point ofthe threaded area 508 a, 508 b. Thus, in some embodiments, the sleeve654 and the sleeve sliding seal 656 may be eliminated or replaced.

FIG. 13B illustrates a lengthened access sheath 500. To increase thelength of the working lumen, the short proximal portion 506 may beremoved and an extender 510 having a length longer than the shortproximal portion 506 may be attached to the coupling extender 502. Inthe illustrated embodiment, the extender 510 comprises a generallytubular body 512 with a distal end 514 and a proximal end configuredwith a complementary retention structure (e.g., threads 508 a and 508 bin the illustrated embodiment) for releasably engaging the couplingextender 502. The access sheath 500 can also comprise an instrumentationvalve 652, a length of expandable sheath tubing 102, and an optionalsealing sleeve 654, which further comprises a sleeve sliding seal 656.

In this manner, by coupling the extender 510 to the coupling extender502, the length of the working lumen 108 may be increased allowing thesurgeon to advance the distal end of the access sheath 500 further intothe patient. In a modified embodiment, the coupling extender 502 may beintegrally formed with the access sheath 500. In addition, the surgeonmay be provided with more than one length of extender 510. In addition,the proximal end of the extender 510 may be configured such that it canbe coupled to a second extender (not shown). The extender 510 and/or theshort distal portion 506 may also be provided as part of a kit with theassembly 150. In this embodiment, the extender 510 is releasably affixedto the proximal end of the access sheath 500 by way of threadedattachment, but such attachment may also be accomplished by way oflatches, snaps, bayonet mounts, and the like. As shown in FIG. 13B, theextender 510 may also include a sleeve 654 and sealing member 656configured as described above to provide a seal between the extender 510and the coupler 502.

FIG. 13C illustrates another embodiment for increasing the length of theworking lumen 108 after an access sheath 600 has been wholly orpartially deployed. In this embodiment, the proximal end 602 of theaccess sheath 600 is coupled, for example using threads or a bayonetmount, or integrally formed with an inner telescoping member 604, whichcomprises an elongated tubular body 606. An outer telescoping member 605is positioned over the inner telescoping member 604 and furthercomprises a flange 609 positioned at the proximal end of the outertelescoping member 605. As shown in FIG. 13C, in a first position, theinner and outer telescoping members 604 and 605 overlap each other toprovide a working lumen of a first, shorter length. By withdrawing theouter telescoping member 605 and reducing the overlap between the twocomponents 604 and 605, the length of the working lumen 108 may beextended.

The inner telescoping member 604 and the outer telescoping member 605preferably include corresponding structures 612 a and 612 b for limitingthe axial movement between the inner and outer telescoping members 604and 605. Any of a variety of corresponding structures may be providedbetween the inner telescoping member 604 and the outer telescopingmember 605 for limiting axial movement between these components. Thesestructures may include, but are not limited, threads, latches, prongs,interference fit, press fit and the like. In the illustrated embodiment,the corresponding structures comprise one or more lateral orcircumferential grooves or indentations 612 a formed on the innersurface 614 of the outer telescoping member 605 and lever arms 612 bformed on the proximal end of the inner telescoping member 604. In theillustrated arrangement, the lever arms 612 b lie between slots 616extending from the proximal end of the inner member 604. The slots 616are one of many ways to create a cantilever spring effect in the leverarms 612 b, integral to and in a cost-effective way, on the elongatedtubular body 606. The lever arms 612 b also comprise radially extendingprotrusions 618. The extending protrusions 618, the edges of theindentations 612 a, or both, may be beveled or rounded to permit thelever arms 612 b to deflect inward when an axial force is applied tochange the length of the sheath 600. With reference to FIG. 13C, in thefirst position, the lever arms 612 b engage the proximal mostindentation 612 a of the outer member 605 thereby securing the axialposition of the inner and outer members 604 and 605. To lengthen theworking lumen 108, sufficient proximal force is applied to the outermember 605, against an opposite force applied to the proximal end 602 ofthe access sheath 600, to cause the lever arms 612 b to deflect inwardlyallowing the outer member 605 to move proximally with respect to theinner member 604. The outer member may be withdrawn until the lever arms612 b engage a more proximal indentation 612 a. In this manner, thelength of the working lumen may be increased, or decreased by movementin the opposite axial direction. A sealing member 620 (e.g., an O-ring)is preferably provided between the inner and outer members 604 and 605.In the illustrated arrangement, the sealing member 620 is positionedwithin a circumferentially disposed recess 622 positioned on the innerdiameter and near the distal end of the outer member 605.

FIGS. 13D and 13E illustrate another embodiment for increasing, ordecreasing, the length of the working lumen 108 after an access sheath600 has been wholly or partially deployed. The proximal end of thesheath 600 may be coupled, using threads, bayonet mounts, etc., or itmay be formed integrally with the length changing structures. As withthe previous embodiment, this embodiment includes inner and outertelescoping members 604 and 605 with corresponding structures 612 a and612 b. In this arrangement, the structure 612 b on the inner member 604comprises one or more tabs 612 b, which engage threads 618 a formed onthe inner surface of the outer member 605. Threads 618 a may comprise acomplete 360-degree revolution about the corresponding part or less thana full revolution such as in a Luer lock and/or other combinations ofradial and axial grooves. In an embodiment, there are between 2 and 20complete 360-degree turns necessary to cause the tabs 612 b to traversethe length of the outer member 605. . The inner member 604 may furthercomprise one or more slots 670 running parallel to the longitudinal axisof the inner member 604 and disposed on the inner diameter of said innermember 604. The elongating structure comprises an extender tube 650 thatterminates at its proximal end with an enlarged region 651 suitable forgripping. The extender tube 650 may further comprise an instrumentationvalve 652 as described above. The extender tube 650 may further compriseone or more radially outwardly directed pins or fins 672 that engage theslots 670 in the inner member 604. The pins or fins 672 prevent rotationof the enlarged region 651 relative to the access sheath 600 so thatinstrumentation alignment is maintained while the lengthening orshortening process occurs. To extend the lumen 108, the outer member 605is rotated with respect to the inner member 604, moving the extendertube 650 and the outer member 605 from the first position, shown in FIG.13D, to a second, lengthened position as illusrated in FIG. 13E. As thelumen 108 is lengthened, the overlap between the extender tube 650 andouter member 605 and the inner member 604 is reduced. The extender tube650 rotates relative to the outer member 605 but does not rotaterelative to the inner member 604, which is affixed to the access sheath600.

In some applications, it may be desirable to increase the diameter ofthe working lumen 108. Referring to FIG. 1 and FIG. 4, in oneembodiment, a second deployment catheter (not shown) may be provided.The second deployment catheter a includes radially enlargeable expansionstructure such as a balloon that has an expanded diameter that is largerthan the expanded diameter of the first balloon 310. If it is desirableto expand the working lumen to a diameter that larger than the originalexpanded diameter, the surgeon may insert the second deployment catheterinto the lumen 108 and inflate the balloon to the second largerdiameter. The expansion of the second balloon may increase the diameterof the sheath 100 by unfolding or uncreasing additional folds or creasesin the access sheath 100. In another embodiment, the sheath tubing 102may be plastically deformed to a larger diameter. In another embodiment,instead of using the second deployment catheter the, the first balloon310 of the deployment catheter 300 may be configured to expand to morethan one diameter. In another embodiment, an internal plastic sleeve isinserted on the inside of the sheath 100. The internal plastic sleeveserves to limit the expansion diameter of the sheath 100 by the firstballoon 310. The internal plastic sleeve is torn or removed after thesecond, larger balloon catheter 310 is expanded inside the first lumen108 to permit additional expansion of the working lumen 108.

FIGS. 14A and 14B are schematic illustrations of another modifiedembodiment of an access sheath assembly 680. The assembly comprises anaccess sheath 600 with a proximal end 602, which may be configured asdescribed previously. The proximal end 602, may be coupled to a proximalhub 603 which may further be coupled to or integrally formed with aninflation hub 606. The inflation hub 606 may include a proximal fitting(e.g., a Luer fitting) 608 and an inflation fitting (e.g. a Luerfitting) 610. The proximal fitting 608 is configured to permit guidewirepassage into a through lumen of an expansion assembly 622. The inflationhub 606, in an embodiment, may be connected to the proximal hub 603using a detent 634 and a clip 636 to permit positive, releaseableengagement. Such releaseable attachment of the inflation hub 606 and theproximal end 604 permits the assembly 680 to be inserted into a patientas a unit, thus providing for greater control during the insertionphase.

The sheath 600 is preferably constrained in a smaller profileconfiguration by a jacket 612 as described above. In one embodiment, thejacket 612 is configured such that it may be partially or wholly torn byinjecting, under pressure, a fluid into the jacket 612. With referenceto FIG. 14A, the jacket 612 includes an outer layer 614 a, an innerlayer 614 b and a seal 614 c positioned at the distal end of the jacket612. The outer layer 614 a, the inner layer 614 b and the seal 614 c,define an annulus or lumen 616, which is connected by a conduit 618 toan inflation fitting 620 (e.g., a Luer or Luer lock fitting).

With continued reference to FIG. 14A, the assembly 680 further comprisesan expansion assembly 622, which in one embodiment comprises aninflatable balloon 624. The balloon 624 is mounted on a balloon cathetershaft 626, which defines an inflation lumen 628. The shaft 626 mayinclude one or more openings 630 for communicating with the interior 632of the balloon 624. The openings 630 may be scythed, drilled, orotherwise created openings in the side wall of the shaft 626. The distalend of the inflation lumen 628 may be closed with a sealing valve 634positioned within, or against, the lumen 628. In this manner, theassembly 6800 may be inserted over a guidewire extending through thelumen 628. The guidewire may then be removed from the lumen 628 and thesealing valve 634 may be pushed open through the lumen 628. In oneembodiment, the sealing valve 634 may be pushed open with a guidewire.Removal of the guidewire may permit the valve 634 to close. With thedistal end of the lumen 628 closed, the balloon 624 may be inflated byinjecting an inflation fluid through the balloon inflation fitting 610.Alternative embodiments of this single lumen, valved configurationinclude dual or multiple lumen tubes that have separate lumens forguidewires and balloon inflation, or coaxial multiple extrusion designs.

To partially or wholly tear the jacket, inflation fluid, such as water,saline, gas, contrast media, or the like, is injected though conduit 618into the jacket lumen 616 until the jacket 612 disrupts or forms a tear640 a as shown in FIG. 14B. Such disruption occurs when the pressurewithin the jacket lumen 616 exceeds the strength of the jacket 612 wall.The jacket 612 may be provided with score lines, thinned regions and thelike to promote tearing or disruption in a certain manner (e.g., incertain directions or certain regions). In one embodiment, the inflationfluid may be used to initialize tearing of the jacket 612. After thejacket 612 begins to tear or disrupt, the jacket 612 may be proximallywithdrawn to complete the tearing or disruption of the jacket 612. Thejacket 612 may then be removed from the sheath 600. In anotherembodiment, inflation may disrupt the jacket 612 such that the sheathmay expand substantially to its fully expanded configuration.

FIGS. 15A-E illustrate another modified embodiment an access sheathassembly 700. In this embodiment, the assembly 700 may include an accesssheath 100, jacket 200 and deployment catheter 300 as described above.For simplicity, only the access sheath 100 and the expandable member 310of the deployment catheter 300 have been illustrated in FIGS. 15A-15E.

With reference to FIGS. 15A-15E, the assembly 700 includes a pluralityof releasable retention structures 702 and 704 between the access sheath100 and the expandable member 310. Any of a variety of releasableretention structures may be provided between the sheath 100 and theexpandable member 310. These structures may include, but are not limitedto, rails, hooks, latches, prongs, interference fit, press fit and thelike. The releasable retention structures are, in an embodiment, axiallyelongate structures with axial lengths approximating those of theexpandable member 310. Provision is made to withdraw the expandablemember 310 and its corresponding releasable retention structureproximally to remove the expandable member from the sheath 100. In anembodiment, the expandable member 310 may be reinserted into the sheath100 and the releasable retention structures realigned and re-engaged. Inthis embodiment, alignment devices are provided to facilitate correctpositioning of the releasable retention structures so that they areeasily re-engaged when the expandable member 310 is re-inserted into thesheath 100. Suitable alignment devices include, but are not limited to,keyholes, embossed, raised, or printed markings, or geometries thatpermit insertion only in one or more pre-determined rotationalorientations. In the illustrated embodiment, the releasable retentionstructures comprise a track member 702, which may be coupled to thesheath 100 by a support member 714, and a rail member 704, which may becoupled to or integrally formed on the outer surface of the expandablemember 310. As shown, FIG. 15D, the track member 702 defines a recessedportion 715 that is sized and configured to releasably engage the railmember 704 in a slip or interference fit. In addition, the track member702 and/or the rail member 704 may be made of an elastic material thatpermits deformation as the two members engage each other. Preferably,the assembly includes at least two and often at least three pairs oftrack members 702 and rail members 704 that are spaced across thecircumference of the expandable member 310.

With reference to FIGS. 15A and 15B, in use, the expandable member 310and the sheath 100 may be initially coupled together by the releasablestructures 702 and 704 when the sheath is in the collapsed, smallerprofile configuration. The expandable member 310 may then be expanded todilate the access sheath 100 as described above. With the sheath 100expanded, the expandable member 310 may be withdrawn from the accesssheath 100 such that the working lumen 108 may be used as describedabove. In another embodiment, the expandable member need not beinitially coupled to the sheath 100 by the releasable structures 702 and704.

When the surgical or diagnostic procedure is complete, the expandablemember 310 may be inserted into the access sheath 100 such that thereleasable retention structures 702 and 704 engage each other. Theexpandable member 310 may then be collapsed (e.g., by withdrawing theinflation fluid). The withdrawal of the inflation fluid will result in aradially inwardly directed force on the expandable member 310. As theexpandable member 310 collapses, the connection between the structures702 and 704 radially pulls the sheath 100 inwardly such that the sheath100 collapses with the expandable member 310. The expandable member 310and the access sheath 100 may then be withdrawn from the patient. Inthis manner, the diameter of the access sheath 100 may be reduced beforeit is withdrawn from the patient.

In a modified embodiment, a separate collapsible member is provided forcollapsing the sheath 100. The collapsible member may be configured asthe expandable member 310 described above. In such an embodiment, thecollapsible member may include the corresponding structure 704 while theexpandable member may be formed without the corresponding structure 704.In another embodiment, the separate collapsible member is different fromthe expandable member 310 and is used only for collapsing the sheath100. In this embodiment, the collapsible member may be configured as acollet or other mechanical radial compression device that hooks onto thesheath 100 from the inside.

FIG. 16 illustrates a side view of another embodiment of an expandablepercutaneous sheath 1600. The sheath 1600 can comprise a sheath assembly1602 and a dilator assembly 1604, which can be configured as describedabove. In FIG. 16, the dilator assembly 1604 is shown as being withdrawnslightly in the proximal direction from the sheath assembly 1602 toreveal certain components. In addition, the sheath assembly 1602 hasbeen shown with a breakaway view of the distal end to reveal the dilatorassembly 1604 therewithin. The sheath assembly 1602 can further comprisea sheath hub 1606 and the dilator assembly 1604 can further comprise adilator hub 1608. In the illustrated embodiment, the dilator hub 1608can comprise an anti-rotation tab or pin 1610, an outer support collar1612, and an inner support collar 1614. In FIG. 16, the dilator hub 1608has been shown in breakaway view to reveal the inner support collar 1614and the anti-rotation tab 1610. The sheath hub 1606 can further comprisean anti-rotation slot 1616. The sheath assembly 1602 can also comprise asheath tube 1618 while the dilator assembly 1604 can further comprise adilator shaft 1620, a dilator balloon 1622, and a guidewire lumen 1624.

With continued reference to FIG. 16, the sheath hub 1606 can be aseparate polymeric or metallic component, which can be bonded to, ormechanically or other wise coupled to, the sheath tubing 1618. Thesheath hub 1606, in a preferred embodiment, can be a diametricenlargement on the proximal end of the sheath tubing 1618 and canfurther be integral to the sheath tubing 1618. The sheath tubing 1618preferably is capable of remodeling or deforming to become elliptical oroval as described above and the sheath hub 1606, in an embodiment, isalso capable of deforming or remodeling with the sheath tubing 1618. Thedilator hub 1608, in an embodiment, comprising the anti-rotation pin1610, the outer support collar 1612, and the inner support collar 1614.In one embodiment, the hub 1608 has all three elements integrally formedto each other or bonded to each other. The integral forming can be doneby machining, injection molding, thermoforming, or the like. Theguidewire lumen 1624 is an interior through lumen, preferablyconcentrically disposed at the center of the dilator shaft 1620,although it could also be an off-center through lumen.

In an embodiment, the dilator hub 1608 is keyed so that when it isinterfaced to, or attached to, the sheath hub 1606, the two hubs 1608and 1606 cannot rotate relative to each other. This is beneficial sothat the balloon 1622 (which can be configured as described above) orthe dilator shaft or tubing 1620 do not become twisted due toinadvertent rotation of the dilator hub 1608 relative to the sheath hub1606. A twisted balloon 1622 has the potential of not dilating fullybecause the twist can hold the balloon 1622 tightly to the dilator shaft1620 and cab prevent fluid from fully filling the interior of theballoon 1622. Twisting of the dilator shaft 1620 or balloon 1622 canalso have the potential for restricting guidewire movement within theguidewire lumen 1624 or adversely affecting inflation/deflationcharacteristics of the balloon 1622. Thus, the anti-rotation feature ofthe two hubs 1608 and 1606 is advantageous. The anti-rotation featurescan, in another embodiment, include mechanisms such as, but not limitedto, one or more keyed tabs 1610 on the sheath hub 1606 and one or morecorresponding keyed slot 1616 in the dilator hub 1608. In anotherembodiment, the sheath hub 1606 and the dilator hub 1608 can have one ormore flat sides which are configured to prevent rotation between the twoelements.

In the illustrated embodiment, axial separation motion between thedilator hub 1608 and the sheath hub 1606 can easily disengage the twohubs 1608 and 1606 while rotational relative motion is prevented by thesidewalls of the tabs and slots. A draft angle on the sidewalls of thetabs and the slots cab further promote engagement and disengagement ofthe anti-rotation feature. In another embodiment, the sheath hub 1606 isreleasably affixed to the dilator hub 1608 so the two hubs 1608 and 1606are coaxially aligned and prevented from becoming inadvertantlydisengaged or separated laterally. In this embodiment, the dilator hub1608 and the sheath hub 1606 can be connected at a minimum of 3 points,which prevent lateral relative motion in both of two substantiallyorthogonal axes. In a preferred embodiment, the two hubs 1608 and 1606can be engaged substantially around their full 360-degree perimeter.Manual pressure can be sufficient to snap or connect the two hubs 1608and 1606 together as well as to separate the two hubs 1608 and 1606.

FIGS. 17A-B are side views of another embodiment of an expandablepercutaneous sheath 1700 comprising a sheath assembly 1702 and a dilatorassembly 1704, which can be configured as described above. In thisfigure, the dilator assembly 1704 is shown as being fully inserted intothe sheath assembly 1702. The sheath assembly 1702 has been shown with abreakaway view of the distal, expandable end of the sheath tube 1718 toreveal the dilator assembly 1704 residing within. The sheath assembly1702 can further comprise a sheath hub 1706 and the dilator assembly1704 further comprises a dilator hub 1708. The hubs 1706, 1708 can beconfigured as described above with reference to FIG. 16. The sheathassembly 1702 further comprises a sheath tube 1718 while the dilatorassembly 1704 further comprises an inner dilator shaft 1720, a dilatorballoon 1722, a guidewire lumen 1724, an outer sheath tube 1726, adistal balloon bond 1728 (where the balloon 1722 can be bonded orotherwise coupled to the shaft 1720), and a distal fairing 1730. Thesheath hub 1706 can be a diametric enlargement of proximal end of thesheath tube 1718.

Referring to FIG. 17A, the distal end of the sheath 1700 in thisembodiment has been configured for added strength. The distal balloonbond 1728 can receive significant stress when the sheath 1700 isadvanced through subcutaneous tissue, muscle tissue, and the like. Thus,it is beneficial to reinforce the distal balloon bond 1728. Thisincreased strength can be accomplished by increasing the diameter at theballoon bond 1728. In one embodiment, the enlarged diameter portion ofthe shaft 1720 has a diameter that is greater than an average diameterof the shaft 1720 positioned within the sheath 1700. The increasedballoon bond 1728 diameter increases the surface area of the bond 1728.Furthermore, the outer tubing 1726 can be fabricated from a 72D Hytrelmaterial that has substantially similar melt temperatures as that of theballoon 1726, thus further increasing bond 1728 strength. For example,in one embodiment, the outer tube 1726 can be extended distally and canbe bonded to the balloon 1722. The outer tube 1726 can further be heatformed to create a fairing 1730 that tapers from the diameter of thedistal balloon 1722 bond 1728 to the diameter of the inner tubing 1720.The guidewire lumen 1724 can reside as the central lumen of the innertube 1720 and can extend through the distal end and the proximal end ofthe dilator 1704. Beyond increasing the strength of the distal balloonbond 1728, the larger diameter provided by the outer tube 1726 can be abetter diameter match for the balloon 1722, which can have inflateddiameters of 24 to 40 French or more. In large diameter balloons 1722,it can be difficult to make a small balloon bond region so a largerballoon bond region can be easier and less expensive to fabricate. Thelength of the distal balloon bond 1728 can range between 0.1-inches and1.0-inches with a preferred range of 0.125 to 0.50-inches. The distalballoon bond can be created using heat welding or using adhesives suchas, but not limited to ultraviolet light curing polyurethane adhesives,Cyanoacrylate, and the like.

FIG. 17B illustrate radiopaque markers 1732 that can be visualizedthrough windows 1734 cut in the wall of the outer dilator tubing 1726.In order to allow for verification of the position of radiopaque markers1732 that are generally bonded to the inner dilator tubing 1720, it canbe beneficial to cut windows 1734 in the outer dilator tubing 1726. Suchwindows 1734 are preferably scythes or portholes and do not circumscribethe entire outer dilator tubing 1726. The windows 1734 areadvantageously sized so that the radiopaque marker or markers 1732 arevisible through the windows 1734 and through the balloon 1722, which isgenerally fabricated from optically transparent materials. Also visiblein FIG. 17B is the balloon bond. 1728 described above between theballoon 1722 and the outer tubing 1726. The distal taper or fairing 1728can be seen and this taper 1728 can provide a smooth dilating ramp atthe distal end of the sheath system tapering up from the inner tubing1720 to the balloon 1722. The inflation lumen 1736 for the balloon 1722can be a coaxial annulus defined by the space between the balloon 1722and the outer tubing 1726.

In another embodiment, rather than extending the outer dilator tubing1726 to reach under the distal balloon bond 1728, the outer dilatortubing can be cut just distal to the proximal balloon bond and aseparate plug (not shown) can be inserted over the inner tubing 1720 toincrease the bond diameter. The separate plug can be bonded or welded tothe internal tubing 1720 on its inner diameter and to the balloon 1722on its outer diameter. In yet another embodiment, the inner tubing 1720can be fabricated to have a much thicker wall and provide the largediameter for an improved distal balloon bond 1728. In this embodiment,no outer tube 1726 is required. The resulting assembly in thisembodiment, as well as the embodiment where the outer tubing 1726 isextended distally, is generally stiff and displays only moderateflexibility, a generally beneficial property of a percutaneous accesssheath. Such percutaneous access sheaths, suitable for nephrolithotomyand the like, need to have some flexibility to pass through the ribs toreach an upper pole of the kidney but they need to be generally stiffand somewhat spike-like.

FIG. 18 illustrates the distal end of another embodiment of an expandedexpandable percutaneous sheath 1800 comprising a sheath tube 1802 thatcomprises a plurality of bevels 1804 and 1806. The bevels 1804 and 1806in this embodiment are configured so that two edge planes are presentand meet at a point 1808 off-center at the distal end of the sheath tube1802. In this figure, the expanded dilator balloon 1810 is shownresident inside the sheath tubing 1802. The use of one bevel 1804 canleave the sheath tubing 1802 with a point 1808 at its distal end. Thesecond bevel 1806 can be useful to tailor the amount of sharpnessdesired at the distal end of the sheath tube 1802 and the ratio of thesize of bevel 1806 versus bevel 1804 can change the location of thepoint 1808 on the distal end of the sheath tube 1802. The angle betweenthe plane of the bevel 1804 and 1806 and the plane perpendicular to thelongitudinal axis of the sheath tube 1802 can range between 10 degreesand 80 degrees. The preferable range of angles is between 30 and 70degrees. The angle of bevel 1804 can be the same as, or different than,the angle of bevel 1806. In another embodiment, the sheath tube 1802 cancomprise three or more bevels on the distal end.

It will be apparent from the disclosure herein that the percutaneousaccess assemblies, and/or the methods described herein may also findutility in a wide variety of diagnostic or therapeutic procedures thatrequire an artificially created or natural access tract. For example,the embodiments described herein may be used in many urologicalapplications (e.g., the removal of ureteral strictures and stones, thedelivery of drugs, RF devices and radiation for cancer treatment, etc.).In such applications, the percutaneous access sheath 100 may have alength of about 30-300 cm with an unexpanded diameter of about 7-20French and an expanded diameter of about 14-60 French. The sheath 100may also be used in many gastrointestinal applications, which requirethe introduction of a surgical retractor (e.g., to the removalgallstones and appendix procedures). In such applications, thepercutaneous access sheath 100 may have a length of about 10-50 cm withan unexpanded diameter of about 3-15 French and an expanded diameter ofabout 15-60 French. The percutaneous access sheath 100 may also be usedas an access catheter for many gastrointestinal applications (e.g.,colon therapies, esophageal treatment and the treatment of bowelobstructions). In such applications, the percutaneous access sheath 100may have a length of about 30-300 cm with an unexpanded diameter ofabout 7-40 French and an expanded diameter of about 14-120 French.

The sheath may also be used in many cardiovascular applications (e.g.,to provide access for minimally invasive heart bypass, valve replacementor the delivery of drugs or angiogenesis agents). In such applications,the percutaneous access sheath 100 may have a length of about 30-300 cmwith an unexpanded diameter of about 3-12 French and an expandeddiameter of about 5-30 French. For vascular applications (e.g.,minimally invasive access to the aorta or contralateral leg arteries forthe treatment of, for example, an abdominal aortic aneurysm), thepercutaneous access sheath 100 may have a length of about 30-300 cm withan unexpanded diameter of about 5-30 French and an expanded diameter ofabout 15-75 French. For gynecological applications (e.g., endometrialtherapies, delivery of drugs, delivery of cancer agents, sterilizationprocedures, etc.), the percutaneous access sheath 100 may have a lengthof about 10-100 cm with an unexpanded diameter of about 3-20 French andan expanded diameter of about 6-60 French. The cardiovascular accessembodiment of the expandable sheath comprises valves and seals at theproximal end to prevent blood loss or the ingress of air into thecardiovascular system.

Although the present invention has been described in terms of certainpreferred embodiments, other embodiments of the invention includingvariations in dimensions, configuration and materials will be apparentto those of skill in the art in view of the disclosure herein. Inaddition, all features discussed in connection with any one embodimentherein can be readily adapted for use in other embodiments herein. Theuse of different terms or reference numerals for similar features indifferent embodiments does not imply differences other than those whichmay be expressly set forth. Accordingly, the present invention isintended to be described solely by reference to the appended claims, andnot limited to the preferred embodiments, disclosed herein.

1. A percutaneous access system for providing minimally invasive access,comprising: an access sheath comprising an elongate tubular body thatdefines a lumen, at least a portion of the elongate tubular body beingexpandable from a first, folded, smaller cross-sectional profile to asecond, greater cross-sectional profile, the access sheath having adistal end and a proximal end, the proximal end comprising an sheathhub, the sheath hub including an anti-rotation member; a releasablejacket carried by the access sheath to restrain at least a portion ofthe elongate tubular structure in the first, folded, smallercross-sectional profile; and an expandable member positioned within theelongate tubular body and configured to expand the elongate tubular bodyfrom the first, smaller cross-sectional profile to the second, greatercross-sectional profile, the expandable member having a distal end and aproximal end, the proximal end including an expandable member hub with acomplementary anti-rotational member configured to mate with theanti-rotational member of the sheath hub and limit rotation between theaccess sheath and the expandable member.
 2. The percutaneous accesssystem of claim 1, wherein the elongate tubular body includes at leastone crease along which the elongate tubular body folds in the first,folded, smaller cross-sectional profile.
 3. The percutaneous accesssystem of claim 1, wherein the expandable device comprises an inflatableballoon.
 4. The percutaneous access system of claim 1, wherein theanti-rotational member of the sheath hub comprises a tab and thecorresponding anti-rotational member of the expandable member hubcomprises a slot configured to receive the tab.
 5. The percutaneousaccess system of claim 4, wherein the expandable member hub includes acup like member that extends over the slot and tab when the expandablemember hub is engaged with the sheath hub.
 6. The percutaneous accesssystem of claim 5, wherein the expandable member hub and the sheath hubengage each of other in a snap fit.
 7. A percutaneous access system forproviding minimally invasive access, comprising: an access sheathcomprising an elongate tubular body having a proximal end and a distalend and defining an axial lumen, at least a portion of the elongatetubular body being expandable from a first, smaller cross-sectionalprofile to a second, greater cross-sectional profile; a releasablejacket carried by the access sheath to restrain at least a portion ofthe elongate tubular member in the first, smaller cross-sectionalprofile; an expandable member positioned within the elongate tubularbody and configured to expand the elongate tubular body from the first,smaller cross-sectional profile to the second, greater cross-sectionalprofile, the expandable member comprising an elongated shaft and aballoon having a distal end and a proximal and being positioned aroundthe elongated shaft, the distal end of the balloon being bonded to anenlarged diameter portion of the elongated shaft, the enlarged diameterportion of the elongated shaft having a diameter greater than an averagediameter of the elongated shaft positioned within the elongate tubularbody.
 8. A percutaneous access system for providing minimally invasiveaccess, comprising: an access sheath comprising an elongate tubular bodyhaving a proximal end and a distal end and defining an axial lumen, atleast a portion of the elongate tubular body being expandable from afirst, smaller cross-sectional profile to a second, greatercross-sectional profile; a releasable jacket carried by the accesssheath to restrain at least a portion of the elongate tubular member inthe first, smaller cross-sectional profile; and an expandable memberpositioned within the elongate tubular body and configured to expand theelongate tubular body from the first, smaller cross-sectional profile tothe second, greater cross-sectional profile, the an expandable memberhaving a distal end and a proximal end, the expandable member carryingat least one radiopaque member within the access sheath; wherein theaccess sheath includes at least one opening in the elongate tubularbody, the at least opening being positioned generally over the at leastone radiopaque member.
 9. The percutaneous access system of claim 8,wherein the expandable member includes a plurality of radiopaque membersand the elongate tubular body includes a plurality of openings eachaligned with one the plurality radiopaque members.
 10. A percutaneousaccess system, for providing minimally invasive access, comprising: anelongate tubular body that defines a lumen, at least a portion of theelongate tubular body being expandable from a first, folded, smallercross-sectional profile to a second, greater cross-sectional profile; areleasable jacket carried by the access sheath to restrain at least aportion of the elongate tubular structure in the first, smallercross-sectional profile; an expandable member positioned within theelongate tubular body and configured to expand the elongate tubular bodyfrom the first, smaller cross-sectional profile to the second, greatercross-sectional profile; and means for preventing rotation about alongitudinal axis between the elongate tubular body and the expandablemember.
 11. A percutaneous access assembly for providing minimallyinvasive access, comprising: an elongate tubular body that defines alumen, at least a portion of the elongate tubular structure beingexpandable from a first, folded, smaller cross-sectional profile to asecond, greater cross-sectional profile, the elongate tubular body has adistal end that forms a distal face which includes two beveled faceswhich are beveled with respect to a longitudinal axis of the elongatetubular body and form a point; a releasable jacket carried by the accesssheath to restrain at least a portion of the elongate tubular body inthe first, smaller cross-sectional profile; and an expandable memberpositioned within the elongate tubular body and configured to expand theelongate tubular body from the first, smaller cross-sectional profile tothe second, greater cross-sectional profile.